Long ago (decades) the dentist would do a bunch of work, then pause to let me swish water in my mouth from the auto-filling cup, and spit into the water-circula

Long ago (decades) the dentist would do a bunch of work, then pause to let me swish water in my mouth from the auto-filling cup, and spit into the water-circulating spitoon-thing before continuing. EDIT: hmm... a "dental engine"? https://en.wikipedia.org/wiki/Dental_engine https://en.wikipedia.org/wiki/Dental_engine better results searching for "dental spit sink"